Liquid crystal display panel

ABSTRACT

A liquid crystal display panel including a first substrate, a second substrate, a liquid crystal layer and an electrode structure is provided. The liquid crystal layer is located between the first substrate and the second substrate. The electrode structure is disposed on the first substrate and comprises a first and a second sub-electrodes. The first and the second sub-electrodes are separated from each other and respectively comprises first and second branch portions. The first branch portion comprises a plurality of first branch electrodes. Two adjacent first branch electrodes are substantially parallel to each other and separated from each other by a first interval. The second branch portion comprises a plurality of second branch electrodes. Two adjacent second branch electrodes are substantially parallel to each other and separated from each other by a second interval.

This application is a continuation of application Ser. No. 13/889,724,filed May 8, 2013, which is a division of application Ser. No.12/963,860, filed Dec. 9, 2010 (now patent 8,462,304, issued Jun. 11,2013). This application claims the benefit of Taiwan application SerialNo. 98145117, filed Dec. 25, 2009, the disclosures of these earlierapplications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to a liquid crystal display panel, andmore particularly to a multi-domain liquid crystal display panel.

2. Description of the Related Art

In recent years, display technology has gained significant progress, andthe market demand for liquid crystal display is booming. The displayquality of a liquid crystal display is essential in the displayindustry. Currently, wide angle technology has gradually become animportant factor in the quality assessment of the liquid crystaldisplay. In the wide angle technology, multi-domain vertical alignment(MVA) technology attracts more and more interest.

In general, the liquid crystal display includes two polarizers, a liquidcrystal display panel and a backlight module. The backlight module isused for providing a light source to the liquid crystal display panel,and the liquid crystal display panel is disposed between the twopolarizers. The liquid crystal display panel includes two substrates anda liquid crystal layer which is disposed between the two substrates.Several pixel electrodes are disposed on one of the substrates. Toprovide multi domains, the pixel electrodes are patterned and dividedinto regions. Here, the pixel electrode includes two symmetricsub-electrode structures, for example. Each sub-electrode structureincludes a stem electrode and several branch electrodes. The branchelectrodes are symmetrically connected to the stem electrode.

Referring to FIG. 1, a partial diagram of the liquid crystal pointingarrows corresponding to the liquid crystal layer of a pixel electrode isshown. When a voltage is applied to the pixel electrode, the electricalfield changes the directions of the liquid crystal pointing arrows, asindicated in the region

A1 at the junction between two sub-electrode structures in FIG. 1. Whenthe directions of the liquid crystal pointing arrows in the region A1are chaotic to form nodes, streaks will occur to the display frame ofthe liquid crystal display panel. Therefore, the brightness of theliquid crystal display panel will be decreased during display. Or, thebrightness of the liquid crystal display panel may become inconsistentduring the display of frames so as to deteriorate the display quality.Besides, the generation of streaks normally increases the time for theliquid crystal display panel to resume the stable state. As a result,how to provide a liquid crystal display with excellent display qualityhas become an imminent task for the industries.

SUMMARY OF THE INVENTION

The invention is directed to a liquid crystal display panel which reducethe occurrence of streaks, increase the brightness and shorten the timefor resuming the stable state so as to improve the display quality andproduct competitiveness.

According one embodiment of the present invention, a liquid crystaldisplay panel including a first substrate, a second substrate, a liquidcrystal layer and an electrode structure is provided. The liquid crystallayer is located between the first substrate and the second substrate.The electrode structure is disposed on the first substrate and comprisesa first and a second sub-electrodes. The first and the secondsub-electrodes are separated from each other and respectively comprisesfirst and second branch portions. The first branch portion comprises aplurality of first branch electrodes. Two adjacent first branchelectrodes are substantially parallel to each other and separated fromeach other by a first interval. The second branch portion comprises aplurality of second branch electrodes. Two adjacent second branchelectrodes are substantially parallel to each other and separated fromeach other by a second interval. At least one end edge of the firstbranch electrodes exactly corresponds to one of the second intervals. Atleast one end edge of the second branch electrodes exactly correspondsto one of the first intervals.

The above and other aspects of the invention will become betterunderstood with regard to the following detailed description of thepreferred but non-limiting embodiment(s). The following description ismade with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partial diagram of the liquid crystal pointing arrowscorresponding to the liquid crystal layer of a pixel electrode;

FIG. 2A shows a liquid crystal display device according to a firstembodiment of the invention;

FIG. 2B shows an electrode structure in FIG. 2A;

FIG. 2C shows liquid crystal pointing arrows of the liquid crystal layerin FIG. 2A corresponding to a region in FIG. 2B;

FIG. 3 shows an electrode structure according to a second embodiment ofthe invention;

FIG. 4 shows an electrode structure according to a third embodiment ofthe invention;

FIG. 5 shows an electrode structure according to a fourth embodiment ofthe invention; and

FIG. 6 shows an electrode structure according to a fifth embodiment ofthe invention.

DETAILED DESCRIPTION OF THE INVENTION

The liquid crystal display panel disclosed in the invention areelaboration in a number of embodiments below with accompanying drawings.However, anyone who is skilled in the art of the invention willunderstand that these drawings and disclosures are for elaborationpurpose only, not for limiting the scope of protection of the invention.

First Embodiment

Referring to FIG. 2A, a liquid crystal display device according to afirst embodiment of the invention is shown. The liquid crystal displaydevice includes a liquid crystal display panel 100, a backlight module200 and polarizers 310 and 320. The absorption axes of the polarizers310 and 320 are perpendicular to each other. The liquid crystal displaypanel 100 is disposed between the polarizers 310 and 320. The backlightmodule 200 is used for providing light for the liquid crystal displaypanel 100 to display an image.

The liquid crystal display panel 100 includes a first substrate 110, asecond substrate 120, an electrode structure 130 and a liquid crystallayer 140. The second substrate 120 is substantially parallel to thefirst substrate 110. The liquid crystal layer 140 is located between thefirst substrate 110 and the second substrate 120. The electrodestructure 130 is disposed on the first substrate 110.

Referring to FIG. 2B, an electrode structure 130 in FIG. 2A is shown.The electrode structure 130 includes a first stem electrode 131 t, afirst branch portion 131 b, a second stem electrode 132 t and a secondbranch portion 132 b. Let the first stem electrode 131 t and the firstbranch portion 131 b be viewed as a sub-electrode structure S11, and thesecond stem electrode 132 t and the second branch portion 132 b beviewed as a sub-electrode structure S12, the sub-electrode structuresS11 and S12 are horizontally adjacent to each other and can respectivelybe viewed as a first bright region and a second bright region. When animage is displayed, the first bright region and the second bright regioncan be mixed and displayed in a pixel to produce low color shift effect.Thus, the display quality of the liquid crystal display panel 100 iseven more dedicated.

The first stem electrode 131 t is, for example, cross-shaped, and thefirst branch portion 131 b includes several first branch electrodes 131b 1. The first branch electrodes 131 b 1 are connected to the first stemelectrode 131 t.

The two adjacent first branch electrodes 131 b 1 are substantiallyparallel to each other and separated apart by a first interval d11.Besides, the second stem electrode 132 t is, for example, cross-shaped,and the second branch portion 132 b includes several second branchelectrodes 132 b 1. The second branch electrodes 132 b 1 are connectedto the second stem electrode 132 t. The two adjacent second branchelectrodes 132 b 1 are substantially parallel to each other andseparated apart by a second interval d12. Any of the first branchelectrodes 131 b 1 corresponds to at least part of one of the secondintervals d12, and any of the second branch electrodes 132 b 1corresponds to at least part of one of the first intervals d11.

In the present embodiment of the invention, the end edge E11 of eachfirst branch electrode 131 b 1 is located on a first dummy line L11, andthe end edge E12 of each second branch electrode 132 b 1 is located on asecond dummy line L12. The first dummy line L11 is substantiallyparallel to the second dummy line L12. Let the length of one firstinterval d11 and one first branch electrode 131 b 1 being on the firstdummy line L11 be a unit length U1, and the length of one secondinterval d12 and one second branch electrodes 132 b 1 being on thesecond dummy line L12 be the unit length U1, the first dummy line L11and the second dummy line L12 are, for example, separated apart by ahalf of the unit length U1. That is, if the unit length U1 is 10 μm, thefirst dummy line L11 and the second dummy line L12 are separated apartby 5 μm. Thus, the end edge E11 of any of the first branch electrodes131 b 1 exactly corresponds to one of the second intervals d12, and theend edge E12 of any of the second branch electrodes 132 b 1 exactlycorresponds to one of the first intervals d11.

Referring to FIG. 2C, liquid crystal pointing arrows of the liquidcrystal layer 140 in FIG. 2A corresponding to a region A21 in FIG. 2Bare shown. When pixels are switched between the bright state and thedark state, the fringe field at the junction between the first branchportion 131 b and the second branch portion 132 b guides the liquidcrystal molecules to tilt to a consistent direction, as indicated in theregion A22. Thus, fewer nodes are generated at the junction between thefirst branch portion 131 b and the second branch portion 132 b, so thatthe liquid crystal display panel 100 has fewer occurrences of streaksand brightness drop. According to the simulation results, if the liquidcrystal molecules are distributed as indicated by the liquid crystalpointing arrows in FIG. 1, then the liquid crystal molecules spend about130 ms to resume the stable state. For the liquid crystal display panel100 of the present embodiment of the invention, the occurrence ofstreaks is reduced, and the time for resuming the stable state after theoccurrence of streaks is effectively reduced to 20 ms.

In the present embodiment of the invention, the sub-electrode structureS11 and S12 is, for example, disposed in a pixel. However, anyone who isskilled in the technology of the invention will understand that thesub-electrode structure S11 and S12 can also be disposed in two adjacentpixels so as to reduce the occurrence of streaks, increase brightnessand shorten the time for resuming the stable state.

Second Embodiment

Referring to FIG. 3, an electrode structure 230 according to a secondembodiment of the invention is shown. A first branch portion 231 b of anelectrode structure 230 includes several first branch electrodes 231 b1. The two adjacent first branch electrodes 231 b 1 are substantiallyparallel to each other and separated apart by a first interval d21. Asecond branch portion 232 b of the electrode structure 230 includesseveral second branch electrodes 232 b 1. The two adjacent second branchelectrodes 232 b 1 are substantially parallel to each other andseparated apart by a second interval d22. In the present embodiment ofthe invention, any of the second branch electrodes 232 b 1 correspondsto at least part of one of the first intervals d21, and any of the firstbranch electrodes 231 b 1 corresponds to at least part of one of thesecond intervals d22, so the advantages of the liquid crystal displaypanel equipped with the electrode structure 230 are similar to that ofthe liquid crystal display panel 100 of the first embodiment.

In the present embodiment of the invention, one end of each first branchelectrode 231 b 1 is connected to the first stem electrode 231 t, andthe other end of each first branch electrode 231 b 1 has two cornersformed by an end edge E21 and two sides Si21. The two corners are, forexample, 90°. Furthermore, one end of each second branch electrode 232 b1 is connected to the second stem electrode 232 t, and the other end ofeach second branch electrode 232 b 1 has two corners formed by an endedge E22 and two sides Si22. The two corners are, for example, 90°.

Thus, the end edge E21 of any of the first branch electrodes 231 b 1corresponds to the side Si22 of one of the second branch electrodes 232b 1, and the end edge E22 of any of the second branch electrodes 232 b 1corresponds to the side Si21 of one of the first branch electrodes 231 b1 . Let the length of one first interval d21 and a part of one firstbranch electrode 231 b 1 being on a first dummy line L21 be a unitlength U2, and the length of one second interval d22 and a part of onesecond branch electrode 232 b 1 being on a second dummy line L22 be theunit length U2, the end edge E21 of the first branch electrode 231 b 1and the side Si22 of the adjacent second branch electrode 232 b 1 areseparated apart by a half of the unit length U2, and the end edge E22 ofthe second branch electrode 232 b 1 and the side Si21 of the adjacentfirst branch electrode 231 b 1 are separated apart by a half of the unitlength U2, for example. That is, if the unit length U2 is 10 μm, thenthe end edge E21 of the first branch electrode 231 b 1 and the side Si22of the adjacent second branch electrode 232 b 1 are separated apart by 5μm, and the end edge E22 of the second branch electrode 232 b 1 and theside Si21 of the adjacent first branch electrode 231 b 1 are separatedapart by 5 μm.

Let the unit length U2 of the present embodiment of the invention beequal to the unit length U1 of the first embodiment. The interval debetween a line Le1 formed by several corners of the first branchelectrodes 231 b 1 and a line Le2 formed by several corners of thesecond branch electrodes 232 b 1 is smaller than the interval betweenthe first branch electrode 131 b 1 and the second branch electrode 132 b1 of the first embodiment. In other words, as the corners of each firstbranch electrode 231 b 1 and the corners of each second branch electrode232 b 1 protrude inwardly, the interval de is reduced, so that the widthof the corresponding streak is reduced and the display quality isincreased.

Third Embodiment

Referring to FIG. 4, an electrode structure 330 according to a thirdembodiment of the invention is shown. The electrode structure 330includes a sub-electrode structure S31 including a first stem electrode331 t and a first branch portion 331 b, and a sub-electrode structureS32 including a second stem electrode 332 t and a second branch portion332 b. The sub-electrode structures S31 and S32 are vertically adjacentto each other.

Since any of second branch electrodes 332 b 1 of the second branchportion 332 b corresponds to at least part of one first interval d31,and any of first branch electrodes 331 b 1 of the first branch portion331 b corresponds to at least part of one second interval d32, theliquid crystal display panel equipped with the electrode structure 330has similar advantages like the liquid crystal display panel 100 of thefirst embodiment.

Fourth Embodiment

Referring to FIG. 5, an electrode structure 430 according to a fourthembodiment of the invention is shown. The electrode structure 430includes a stem electrode 430 t, a first branch portion 431 b and asecond branch portion 432 b. The stem electrode 430 t is, for example,cross-shaped, and the first branch portion 431 b and the second branchportion 432 b are respectively connected to two opposite sides of thestem electrode 430 t.

Since any of second branch electrodes 432 b 1 of the second branchportion 432 b corresponds to at least part of one first interval d41,and any of first branch electrodes 431 b 1 of the first branch portion431 b corresponds to at least part of one second interval d42, theliquid crystal display panel equipped with the electrode structure 430has similar advantages like the liquid crystal display panel 100 of thefirst embodiment.

Fifth Embodiment

Referring to FIG. 6, an electrode structure 530 according to a fifthembodiment of the invention is shown. The electrode structure 530includes a main electrode 530 m, a first branch portion 531 b and asecond branch portion 532 b. The main electrode 530 m has a firstinclined side R1 and a second inclined side R2. The first inclined sideR1 and the second inclined side R2 form an indent. Each first branchelectrode 531 b 1 of the first branch portion 531 b is connected to thefirst inclined side R1 to be located inside the indent. Each secondbranch electrode 532 b 1 of the second branch portion 532 b is connectedto the second inclined side R2 to be located inside the indent.

Since any of the second branch electrodes 532 b 1 corresponds to atleast part of one of the first intervals d51, and any of the firstbranch electrodes 531 b 1 corresponds to at least part of one of thesecond intervals d52, the liquid crystal display panel equipped with theelectrode structure 530 has similar advantages like the liquid crystaldisplay panel 100 of the first embodiment.

According to the liquid crystal display panel and the liquid crystaldisplay device using the same disclosed in the above embodiments of theinvention, through the disposition of the first branch portion and thesecond branch portion adjacent to each other, the occurrence of nodes atthe junction between the first branch portion and the second branchportion can be reduced so as to increase the overall display brightness.Moreover, since the time for resuming the stable state after theoccurrence of streaks is shortened, the display quality can be furtherimproved.

While the invention has been described by way of example and in terms ofthe preferred embodiment(s), it is to be understood that the inventionis not limited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements and procedures, and the scope ofthe appended claims therefore should be accorded the broadestinterpretation so as to encompass all such modifications and similararrangements and procedures.

What is claimed is:
 1. A liquid crystal display panel, comprising: afirst substrate; a second substrate; a liquid crystal layer disposedbetween the first substrate and the second substrate; and an electrodestructure disposed on the first substrate, wherein the electrodestructure comprises first and second sub-electrodes, wherein the firstand the second sub-electrodes are separated from each other andrespectively comprises first and second branch portions, wherein thefirst branch portion comprises a plurality of first branch electrodes,and two adjacent first branch electrodes are substantially parallel toeach other and separated from each other by a first interval, the secondbranch portion comprises a plurality of second branch electrodes, twoadjacent second branch electrodes are substantially parallel to eachother and separated from each other by a second interval, and wherein atleast one end edge of the first branch electrodes exactly corresponds toone of the second intervals, and at least one end edge of the secondbranch electrodes exactly corresponds to one of the first intervals. 2.The liquid crystal display panel according to claim 1, wherein each endedge of the first branch electrodes exactly corresponds to one of thesecond intervals, and each end edge of the second branch electrodesexactly corresponds to one of the first intervals.
 3. The liquid crystaldisplay panel according to claim 1, wherein the electrode structurefurther comprises: a first stem electrode, wherein the first branchelectrodes are connected to the first stem electrode; and a second stemelectrode, wherein the second branch electrodes are connected to thesecond stem electrode.
 4. The liquid crystal display panel according toclaim 3, wherein the first stem electrode is cross-shaped, and thesecond stem electrode is cross-shaped.
 5. The liquid crystal displaypanel according to claim 3, wherein an extended line of the first stemelectrode corresponds to an extended line of the second stem electrode.6. The liquid crystal display panel according to claim 1, wherein theelectrode structure further comprises a stem electrode, wherein thefirst branch portion and the second branch portion are connected to twoopposite sides of the stem electrode, respectively.
 7. The liquidcrystal display panel according to claim 6, wherein the stem electrodeis cross-shaped.
 8. The liquid crystal display panel according to claim1, wherein the end edge of each first branch electrode is located on afirst dummy line, the end edge of each second branch electrode islocated on a second dummy line, and the first dummy line issubstantially parallel to the second dummy line.
 9. The liquid crystaldisplay panel according to claim 8, wherein the length of one of thefirst intervals and one of the first branch electrodes being on thefirst dummy line is a unit length, the length of one of the secondintervals and one of the second branch electrodes being on the seconddummy line is the unit length, and at least one of the first dummy lineand the second dummy line are separated apart by a half of the unitlength.
 10. The liquid crystal display panel according to claim 1,wherein two corners of each first branch electrode are both 90°, and twocorners of each second branch electrode are both 90°.